More than 50,000 people are expected to fill Queensland’s Suncorp Stadium, with tickets selling for hundreds of dollars per seat. It will be televised in more than 150 countries, according to Horn’s sports manager Jim Banaghan.

Pacquiao has lost three of his last eight fights but is said to be keen for a knockout

The boxer’s wife and parents have even been pulled into some of the media attention.

"They’re happy for me but they’re nervous as well. They don’t want to see me get hurt," Horn said.

After Pacquiao’s fight with Floyd Mayweather in 2015 became the most lucrative in history, the Australian bout may be regarded as something of a sideshow. Pacquiao may meet Mayweather for an anticipated rematch.

Pacquiao, 38, is also a serving senator in his native Philippines. During a series of promotional news conferences in Australia in April, Pacquiao appeared more interested in his phone than his opponent.

It was a scene to disappoint fans of boxing trash-talk: two clean-cut fighters speaking politely and respectfully about one another.

Pacquiao is the only boxer in history to win world titles in eight weight divisions

"I know what my opponent is feeling right now is hunger," Pacquiao said.

"I’ve been there. I’ve been there in that situation. When I was starting, when I was young, even at night before I went to sleep, I was thinking about the fight."

Does Horn stand a chance?

Whatever the result, the fight will change Horn’s life. Overnight he will become a millionaire. A victory could go down as one of most important in Australian sporting history.

Legendary promoter Bob Arum, who notably worked with Muhammad Ali, said the huge hometown crowd could hand Horn the advantage to stage a monumental upset.

"If his fight with Pacquiao was in Vegas or Madison Square Garden in New York, I wouldn’t give him much of a chance because I think nerves would take over," he told the Courier-Mail newspaper.

"But the fact that Jeff is going to be fighting in front of so many of his countrymen will calm his nerves and I think he will give a great account of himself."

If Horn wins his career-defining fight, Pacquiao will be granted a customary rematch

Australian fighter Anthony Mundine, himself a three-time world champion, said an upset was possible but warns that 38-year-old Pacquiao is still a force to be reckoned with.

"Even though he is at his end and past his prime, I believe he is still a dangerous fighter," he told the Australian Associated Press. "But anything can happen in boxing."

Horn has been training six days a week before the match, visualising the ring surrounded by thousands of screaming fans and sidestepping inside it with Pacquiao.

Superficially, it’s hard to imagine two more different fighters. Pacquiao spent his childhood living in poverty in the Philippines, and entered politics. Horn grew up in relative prosperity in Australia, and became a teacher. Do they have anything in common?

"We’re both nice guys by the sound of it – except in the ring," Horn said.